Means and method for producing cams



'July A30, 1940.` v K HABE ums um METHOD Fon Pnonucme cms Filed July 5, 1938' v t: zug.; i l 12 l 20 f al." 3 /nvnzof ,6 '.5 Aim 1634.95- By' i 'd Aforneys Patented July 30, 1940 UNITED sTA'tEs PATENT OFFICE 2,209,538 MEANS AND METHOD FOB. PRODUCING CAMS Karl Rabe, Stuttgart, Germany, `assignor to Dr. ing. h. c. F. Porsche, K.G:, Stuttgart,-Zui!en hauscn, Germany, a. company. of Germany.

Application July 5, 1938, Serial N0. 217,545

In Germany July 30, 193'1L 1s claims. (ci. 51-101) Another object of this invention is to provide a device and methodfor the formation of a cam from a master cam form.

A further object of this invention is to provide an improved device and method for the production of a pair of complementary cams. A still further object of this invention is to provide a device and method for the production of a pair of complementary cams from a single master cam form.

A comprehensive object of this invention is the provision of a single device which may be used for the cutting, milling, grinding and/or lapping of a pair of complementary cams from a single master ycam having the shapeoi only one of thecams to be produced.

Other objects of this invention will be apparent with reference to the accompanying drawing wherein:

Fig. 1 is a partially diagrammatic .illustration of the use of a complementary cam pair;

Fig. 2 shows one form of an arrangement according to this invention for the production of cams; and j Fig. 3 is a modied arrangement ofthe construction shown in Fig. 1.

The use of cams for transmitting variable mo,- tion is well known in the vmachine art. Likewise,

the use of a pair of complementary cams for transmitting. variable motion but at the same time positively constraining the movement of the o movedobject is known. Such a. combination is illustrated in Fig. 1 wherein a pair of arms I,l 2

rigidly interconnected with one another have rollers 3, 4 mounted uponitheir respective end s. This rigid assembly is connected for oscillation 45 about an axis B. Cooperating with the rollers e 3, 4, is a complementary cam p air 5, 6 mounted for rotation-about an axis A. The cams 5 and 6 are so formed that contact of the cam 5 with the roller 3 will lgive to the integral assembly com- 50`prising arms I and 2 and rollers 3 and 4 the same movement asis imparted by the cam 6 tol the roller 4. 'I'he advantage of this arrangement over, for example, the use of the single cam 5 acting upon the roller 3, is vthat movement of the moved assembly is constrained due t0 the contact from the following description of this inventionI of the roller 4 upon the cam 6 although the imparted motion is exactly thesame.

Fig.2 discloses an arrangement for the production of a device such as the cam pair 5, 6' of Fig. 1. As illustrated in Fig. 2 a singlemasterform or cam I3 is mounted for rotation about an axis F.

A follower 9 having a contacting face I 0 is also mounted for rotation about an axis C which is parallel to the axis F. A spring -20 is shown as holding the follower against the master cam. A- work piece or pieces to which the complementary cam shapes are to be given is mounted for rotation about'an axis E preferably parallel to the axes C and F of the follower and master cam respectively. The complementary cams formed upon the work piece are designated in the drawing as II and I2. The cams II and I2 are cutor ground upon the Work piece by the use of any suitable grinding or cutting device or devices designated as I6. These cutting devices, in the form ,of the invention here illustrated, are mounted for rotation about an axis D coinciding with the axis C of the follower 9. They are supported upon a pair of arms l, 8 which may be formed as an integral part of the follower. Suitable mounting means are illustrated as shafts I4 and I5 at the respective ends of arms l, 8. Means are provided vfor simultaneously and equally rotatingthe master cam and the.\work piece. Such means may be a common shaft I9 acting-respectively through worm gears I8a and lab upon I the gear wheel lI'Iaa mounted co-axiallywith the work piece and gear wheel I'Ib mounted coaxially with the master cam.

'I'he work pieceis either fed into the space bet tweenthe grinding wheels I6 or the wheels are moved against the Work piece until they have assumed a position determined bythe position of the master form I3. The shaft I9 is then rotated and the grinding operation repeated until the entire circumference of the master form I3 has been followed at which time the work piece will assume theoutlines of the cam pair II, I2. It willbe obvious to those skilled in the art that the arrangement described above is' useful not only for cutting out a .cam pair II, I2 in accordance with the master cam I3, but also for any type of shaping such as milling, grinding, polish# 1 ing or lapping the cam pair. Furthermore, the cam pair may be formed even if only one grinding or cutting wheel isavailable. If the grinding wheel I6 is, for example, first placed upon the shaft I4, the cam lII will be Iformed by following the above described process. `If thewheel I6 is then placed upon the shaft I5 the complementary form I2 can then be made.

In order that the cam pair II, I2 be formed exactly in accordance with the master cam I3, it is preferable that the radius of the follower face I0 bear the same proportion to the size of the master cam I3 as the radius of the grinding wheel I6 bears to the size of the desired cam pair II, I2.

The arrangement according to Fig. 3 is substantially the same as that of Fig. 2 with the exception that the Work piece is mounted upon an axisk E which coincides with the axis F of the master cam. VThe axis C of the double' armed lever 1, 8 bearing the grinding or cutting Wheel I6 is then preferably mounted parallel to the l axis D of the follower arm 9. The double armed lever is however, given the same motion as the follower arm 9 by means of a link 2| pivotally interconnecting these two parts. It will be obvious that .in this form of the invention no speciall connecting means between the master cam and the work piece isnecessary, for these being both mounted upon the same shaft wllof necessity move together. This arrangement is perhaps preferable to that illustrated in Fig. 2 since the axes of the work piece and the master cam being the same, a more exact cutting will result.

It will be obvious to those skilled in the art that variations in the size of the cam pair can be made either by a change in size of the master cam or by an appropriate change in size of the grinding or cutting ,wheels I6. The correctness of the produced cam pair will in such cases not be impaired so long as the geometry of the arrangement is maintained.

It will also be obvious to those skilled in the art that the arrangement described above is not limited to the formation of a cam pair but can be equally advantageously used for the formation of a single cam or its complement or for the formation of any desired shapes in accordance with the shape of a single master form.

Various changes of the 'above described arrangement may be made without departing from the scope of this invention. It is not necessary that the grinding or cutting means be mounted in the manner indicated so long as they will partake of the correct motion. The relative size and exact positioning of the various parts is not limited to those shown on the drawing but may be made within a wide range of dimensions necessitated by the size of the parts to be produced, the size of the master form, etc. `The follower and grinding wheel support need not be rotatably mounted, but may be positioned upon slides, depending upon the type of motion which it is desirable .to transmit to. the moved element and the relationship of this element to the cam pair. The arrangements illustrated in Figs. 2 and 3 have been designed to produce a cam pair acting in the manner proscribed by Fig. 1. If the proscribed motion to be imparted is different, the grinding setup will vary accordingly, as will be obvious to those skilled in this art, it being only important that the geometry of the arrangement as herein taught for grinding a complementary cam pair be maintained.

Accordingly, I do not intend that the scope of this invention be limited to the two forms above described, but only by the scope of the claims which follow.

I claim:

1. In combination, a rotatably mounted master form, means adapted to rotatably support a pair of co-axially mounted'work pieces, a rotatably 'of said shaping devices being mounted follower, the axis of rotation of which is substantially parallel to the axes of rotation of the master form and the work piece support, a pair of shaping devices interconnected with said follower and partaking of its rotatable movement, one of said shaping devices being positioned to cooperate with one work piece and the other positioned to cooperate with the other work piece, said shaping devices being mounted at an angle to one another along an arc the plane of which is perpendicular to"the axis of rotation of said follower, means urging said follower against said master form, and means for simultaneously rotating said master form and said work piecesupport.

2. The combination according to claim 1 in which the axis of rotation of said work piece support is parallel to the axis of rotation of said master form.

3. The combination according to claim 1 in which the axis of rotation of said work piece support coincides with the axis of-rotation of said master form.

4. The combination according to claim 1 in which said shaping devices are mounted on an integral portion of said follower.

5. The combination according to claim 1, in combination with a double-armed rotatably mounted lever, the axis of rotation of which is substantially parallel to the axis of rotation of said follower, and a link pivotally interconnecting said follower and said lever, said shaping devices being respectively mounted on opposite arms.

6. The combination according to claim 1 in which said shaping devices are mounted on an integral portion of said follower, and the axis of rotation of said Work piece support is' substantially parallel to the axis of rotation of said master form.

'1. The combination according to claim 1, in combination with a double-armed rotatably `mounted lever, the axis of rotation of which is substantially parallel to the axis of rotation of saidfollower, and a link pivotally interconnecting said follower and said lever, said shaping devices being respectively mounted on opposite arms, and the axis of rotation of said work piece support coinciding with the axis of rotation of said master form.

'8. The combination according to claim 1 in which the master form has the shape of only one of the devices to be produced.

9. In an arrangement for the production of a complementary cam pair, in combination, a rotatably mounted master cam, means adapted to rotatably support a work piece, a follower, means for pressing said follower against said master cam, a pair of supports mounted for movement with said follower, each extending over opposite longitudinally displaced portions of a work piece carried by said work piece support, rotary grinding means mounted on at least one of said supports, and means for simultaneously rotating said master cani and said work piece support.

10. In an arrangement for the'production of a complementary cam pair, in combination, a rotatably mounted master cam, means adapted to rotatably support a work piece, a follower, means for pressing said follower against said master cam, apair of supports mounted for movement with said follower, each extending over opposite longitudinally displaced portions of a work piece carried by said work piecesupport, rotary grindingA means mounted on eac'n of said supports, and

means for simultaneously rotating said master cam and said work piece support.

1l. 'Ihe combination according to claim 10 in -which the master cam has the shape of only one placed portions of a complementary cam blank vin accordance with the outline of a single master cam, the position of one of said grinding means relative to its blank being the same as the position of the cam follower is to have to its 'nished cam.

13. A combination according to claim l in which the axis of rotation of said work piece support is spaced from and parallel to the axis of rotation of said master form, said master form being larger than each of the work pieces to be worked on.

14. In combination, a rotatably mounted master form, a lever pivote'd at a distance from and on an axis parallel to the axis of rotation oi said master form and formed with a cylindrical follower surface contacting said master form, means adapted to rotatably support a work piece, means forl simultaneously rotating said master form and said work piece support, a rotating shaping device for forming the contour of said work piece mounted for oscillation about an axis parallel to the axis of the work piece, the axis of the master form and the axis of the follower surface, and means for so connecting said shaping device for movement with said lever that it is moved Vthrough the Isame angle but a shorter distance than the follower surface, the extent of movement of the shaping device bearing the same rela- 3 tion to the .extent of movement of the follower surface as the radius of curvature of the shaping device bears to the radius of curvature of the follower surface, and as the desired dimensions of the nished work piece bears to corresponding dimensions-of the master form, whereby a largev master, form may be employed to control the formation of a geometrically similar or complementary work piece of a smaller size.V

15. The combination according to claim 14 in which the shaping device is carried by the lever` which carries the follower surface. i6. In combination, a rotatably mounted master form, a pivoted lever formed with a follower surface contacting said master form, a support for a work piece connected for rotation in synchronism with said master form, a shaping device for operating upon a Work piece to be carried for rotation by said work piece support,4 a support. for

said shaping device carried upon a pivot at a distance from said shaping device so connected with said follower lever that angular movement of .the follower lever will impart corresponding angular movement to said shaping device support, the distance of said shaping device from its pivot being smaller than the distance of the follower surface from' its pivot and the follower surface being geometrically similar to the shaping device and bearing the same geometric proportionA thereto as `the master form bears to the work piece to be formed, whereby a large master form may be employed to control thel formation of the geometrically similar contour of a small work piece. l

KARL BABE. 

